Process of producing quinizarin.



SKT AE FQ OSKAR UNGER AND EUGEN MOLINEUS, OF LEVERKUSEN, NEAR COLOGNE, GERMANY, ASSIGNORS TO FARBENFABRIKEN VORM. FRIEDR. BAYER & 00., OF ELBERFELD, GERMANY, A CORPORATION OF GERMANY.

PROCESS OF PRODUCING QUINIZARIN.

No Drawing.

To all whom it may concern:

Be it known that We, OSKAR UNGER and Event: MoLINnUs, doctors of philosophy, chemists, citizens of the German Empire, residing at Leverkusen, near Cologne, Germany, have invented new and useful Improvements in Processes of Producing Quinizarin, of which the following is a specification.

\Ve have found that quinizarin can be obtained with a good yield by condensing parachlorophenol compounds such as para-chlorophenol or its sulfonic acids with phthalic anhydrid by means of concentrated or fuming sulfuric acid containing boric acid.

In order to illustrate the new process more fully the following examples are given, the parts being by weight:

Example 1 80 parts of phthalic anhydrid, 20 parts of boric acid and 23 parts of parachlorophenol are added to 400 parts ofsulfuric acid (96 per cent). The mixture is heated for 3 hours to 150 C., the temperature is then raised to from 180 to 200 C. and kept at this point until the amount of quininariu does not further increase. after cooling poured into 20 times the quan tity of water, the precipitate which separates is collected on a filter then purified by eittraction with a large quantity of boiling water and finally dried. The yield of quinizarin amounts to-7080 per cent. of the theory.

Wfonic acid ofpara chlorophenol.

Example 2 A mixture of 60 parts of parachlorophenol with 200 parts of fuming sulfuric acid (20 per cent.) is heated to from 130-1l0 C. and kept at this temperature until a test portion does not separate any more precipitate, when added to a 12 per cent. solution of common salt, which indicatcs the complete formation of the disul- 200' parts of sulfuric acid (96 per cent), 40 parts. of boric acid and 80 parts of phthalic anhydrid Specification of Letters Patent.

Application filed October 8, 1812. Serial-No. 724,612.

The melt Patented Feb. 17, 1914.

some time the sulfuric-boric-acid-ester having most probably the formula:

C H O,.'SO .B O

separates from the melt in dark blue crystals. .When its amount does not further increase, the melt is allowed to cool and the precipitate is collected on an asbestos filter then washed with sulfuric acid Be.) finally with ice Water and is then dried. On boiling it with water or a solution of soda quinizarin is obtained of excellent purity.

Example 3: 112 parts of the sodium salt of 4L-chlorophenol-2-monosulfonic acid, parts of phthalic anhydrid and 20 parts of boricacid are heated with 400 parts of sulfuric acid monohydrate as described in the preceding examples. The yield of quinizarm 15 equal to the amount obtained When using the equimoleeular quantity of paracl1loro-phen0l.

We claim 1. Process for producing quinizarin, which process comprises condensing a parachlorophenol compound with phthalic acid anhydrid by means of sulfuric acid containing boric acid, substantially as described;

2. Process for producing quinizarin, which process comprises condensing a arachloro-phenol sulfonic acid -Wltl1 phthalic acid anhydrid by means of sulfuric acid containing boric acid substantially as described.

3. Process for producing quinizarin, which process comprises condensing a parachloro-phenol compound with phthalic acid anhydrid by means of concentrated sulfuric a id containing boric-acid, substantially as d scribed. 4

Process for producing quinizarin, which process comprises condensing a parachloro-phenol sulfonic acid with phthalic acicl anh drid b means of concemmtsc l acid anhfiril b means of fumin sulfuric sulfuric acid contmziing 00210 210151 substan-- tially as described 5. Process for prodgcing quinizarin, which process compnsescondensing a pamchloro-phenol compaund Wiah ph'thslic acid anhydrid by means of filming sulfuric acid cuntaini'ng boric 2,4215%, substantially described.

6. Process for precluding quinizarim which process cumnrises wndensing a para- ChlOIWPhGQOl sulIonic acid with phthalic acid. containing is oric acifl, substantially as iliescribadu In cestimnny whereof We have hereunto set 011 hans in the pmsence of two subscribing Witnesses.

CHAS. J. 'Wmmm ALBERT HUME. 

